Bruce Carson leaves the courthouse after appearing in court for a verdict in his case, Tuesday, November 17, 2015 in Ottawa. A one-time senior aide to former prime minister Stephen Harper has been found guilty of influence peddling by Canada’s highest court. THE CANADIAN PRESS/Adrian Wyld

A one-time senior aide to former prime minister Stephen Harper has been found guilty of influence peddling by Canada’s highest court.

Bruce Carson’s case will now be sent back to the trial judge for sentencing after an 8-1 decision by the Supreme Court of Canada that rejects his interpretation of the influence-peddling law.

He could face up to five years in prison.

Carson worked in the Prime Minister’s Office as a senior adviser between 2006 and 2008 and briefly in 2009, during Harper’s tenure.

After leaving the PMO, he tried to use his government connections at what was then called Indian and Northern Affairs Canada, as well as in cabinet, to push the sale of water-purification systems for First Nations communities made by a company known as H2O Pros and H2O Global.

In exchange, Carson had the company pay his then-girlfriend a commission of the sales.

Carson was acquitted at trial after his lawyers argued he couldn’t be guilty of influencing “any matter of business relating to the government” because it was the First Nations communities, not the government, that purchased the water systems.

The Ontario Court of Appeal took a broader view of the wording and, in a split decision, overturned the acquittal. And because of that split, the case automatically went to the Supreme Court.

The Supreme Court followed the same path as Ontario’s highest court. The majority took a broad view of the statement, saying the phrase should include anything that depends on or could be facilitated by the government.

Writing for the majority, Justice Andromache Karakatsanis said federal officials could have made it easier for First Nations to purchase the systems by changing funding terms and conditions to the company’s benefit, or by funding pilot projects that used the company’s systems.

He said the Criminal Code provisions that deal with frauds on the government — including influence peddling — are designed to target behaviour that “risks depriving citizens of a true democracy.”

“Corruption and the sale of influence, whether real or apparent, with government may undermine the integrity and transparency that are crucial to democracy,” Karakatsanis wrote.

“Whether a person accepts a benefit in exchange for a promise to influence the government to change its policies or funding structure, they flout the notion that government decision-making should not be the object of commerce.”

Justice Suzanne Cote was the lone dissenter, arguing the provision is intended to protect actual, not perceived, government integrity.

Cote said Carson needed to have influence over something that was actually related to government operations and not potential changes to federal operations as her colleagues argued.

“The matter of business must relate to the government in reality and not merely be believed by the parties to the agreement to relate to the government,” she wrote.